Shares of U.K. gambling companies slumped Tuesday after a ban on credit-card use was announced. The slump, which hit companies including 888 Holdings 888, -1.51%  , GVC Holdings GVC, +0.17%  , William Hill WMH, -1.08%  and Flutter Entertainment FLTR, -0.02%  , came as the U.K. Gambling Commission announced a banRead More →